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Science rivals open the book of life
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From The Daily Telegraph Feb 12
THE first analysis of the entire set of human genetic instructions was published yesterday, revealing far fewer genes than expected.
Scientists also found that these instructions were strikingly similar across all ethnic groups, with every person sharing 99.99 per cent of their genetic code with all others. The research by rival teams, one public and one privately funded, suggests that the "book of humankind" is even more wonderful and mysterious than previously thought.
It reveals an extraordinary trove of information about human development, physiology, medicine and evolution that will pave the way to personalised medicine. However, the work has been marked by controversy.
Although the teams have worked independently, the public project claims that the private team's analysis relied heavily on its data. Dr Tim Hubbard, of the Sanger Centre near Cambridge, the main institution with public support, said: “This has vindicated the approach of the public domain project.”
Already, treatments are being envisaged based on newly-found genes for asthma and Alzheimer's disease, as well as depression and other mood disorders.
The public team points out in the journal Nature that all current drugs on the market are based on just 483 biological "targets" in the human body. They have now revealed hundreds of thousands more.
This figure reflects the number of proteins in the body. But the surprise is that this vast diversity is described by as few as 26,000 genes - far fewer than previously estimated.
The public team also found that hundreds of human genes appear to have been exchanged with bacteria at some point in evolution.
We also share many genes with more humble organisms - about half with the fruitfly and the nematode worm, and about a fifth with yeast. All that distinguishes an Inuit from a Cockney or an Aborigine, even Britney Spears from Diana Ross, are variations in 300,000 letters in a three billion letter sequence in the human genome.
There are four letters used in the genetic alphabet. Each letter is a chemical unit that forms steps within DNA's ladder-like structure. Variations in the genome's sequence of three billion letters spells out our genes, the instructions to make proteins, the large molecules used to build and operate cells in our body.
Because only 1.1 per cent of the genome consists of genes - the rest appears to be mostly repetitive junk - the biological differences that influence everything from our looks to our intellectual ability boil down to differences between 1,000 and 10,000 genetic letters, according to Dr Craig Venter, of Celera Genomics, the privately funded team.
People from different racial groups can be more genetically similar than individuals within the same group, according to the study his team published in the journal Science. Individual variations in genetic code represent just 0.01 per cent of the sequence of letters.
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